The present invention relates to a method and apparatus to control the traversing motion of a cutting tool supported by an arm that is carried for universal movement by a tunneling machine, particularly a strip-cutting heading machine. More particularly, the present invention relates to such a control for limiting the traversing motion of a cutting tool to the tunnel cross section that is to be driven; the position of the cutting tool is defined in relation to a laser beam projected along in a direction parallel with the desired tunnel axis, and the arm pivoting angles are measured to form corresponding signals while profile control means form signals representing set-point values which are corrected by corresponding signals when the heading machine deviates from its set-point position.
It is a known prior art method to limit traversing motion of a cutting tool while supported for universal movement by a pivot arm on a strip-cutting heading machine to a tunnel cross section that is to be driven wherein the method includes the use of a laser beam projected along the longitudinal tunnel axis for defining the relative position of the tunnel cross section. The range of movement by the cutting tool is limited by using a template which is geometrically similar to the desired tunnel cross section and in which the heading is to proceed. The template is traced by a stop abutment or by a reflective light barrier to form set-point coordinate values for the cutting tool. THe coordinate set-point values are corrected by deviation signals corresponding to deviations by the heading machine from its set-point position.
It has also been disclosed in the past, in regard to a strip-cutting heading machine with a cutting tool supported by a pivot arm to limit the range of universal displacement by the cutting tool to the tunnel cross section relative to a laser beam projected along the longitudinal axis of the tunnel. Such a heading machine is provided with means for detecting offsets and deviations with respect to the laser beam to thereby produce signals which are proportional to the deviations and/or offsets in order to correct the range of permissible movement by the cutting tool. A computer is used to continuously calculate limit coordinates at right angles to measured coordinates which extend through the point of intersection of the cutting tool. In this control system, a mathematical program defines the shape and size of the desired tunnel profile. A signal, proportional to the measured value coordinate of the cutting tool and corrected in accordance with any correction signals which occur, is used to define a point lying in the middle of the position of the cutting tool. This point is tangent to the tunnel profile. The limiting coordinate is constantly compared by the computer with other measured value coordinates of the cutting tool and any motion of the cutting tool beyond the calculated limit value is thus prevented.